Healthy Weight and BMI Range for Older Adults

BMI, Weight and Aging

An obese man eats junk food.
An obese man eats junk food. Sean Gallup/Getty Images

What is a healthy weight and BMI past age 65? When it comes to defining “healthy," medical experts have a tough time. For weight, they typically use a measure that takes into account the total weight of a person and the person’s height. This measure is called BMI (body mass index).

An adult is considered normal or healthy when his or her body mass index is between 18 and 25, and there isn't yet a different range for people older than 65.

A BMI over 25 is classified as overweight and a BMI over 30 is classified as obese, with increased health risks. But does being over the normal/healthy range really negatively impact health, life expectancy and longevity, especially once you are already older?

How Heavy is Unhealthy at Older Ages?

A study published in the 2008 Journal of the American Geriatrics Society set out to determine just that. Researchers collected BMI data of almost 6,000 adult participants, all older than age 65, over multiple years. They paid special attention to when a person would move from “healthy” weight to overweight, or from overweight to obese. Any movement in the other direction (from obese to overweight, for example) was also tracked. They tried to link these changes in weight category with various health conditions. This is what they found:

  • Women who did not have any health conditions and were at a “healthy” weight at age 65 had a life expectancy of 22.1 more years. They spend an average of 9.6 of those years overweight and 5.3 in fair or poor health.
  • Being underweight at age 65 was linked to poor health and shorter life expectancy.
  • Being overweight or obese at 65 was only rarely linked to worse health outcomes or lower life expectancy, compared to those who were at a “healthy” weight at age 65. (Sometimes the overweight and obese had better health outcomes).

    Does That Mean I Can Ignore Being Overweight as I Age?

    Not so fast. Remember that these folks made it to 65 in relatively good health. They could be lucky or genetically immune to the effects of being overweight or obese. What may end up happening is that the “healthy” weight range for a 65-year-old may be higher that a “healthy” weight for a younger person. After all, why should we apply the same weight range for everyone aged 18 to 118?

    Much more data is needed before we truly understand the impact of weight on aging. We can be pretty sure that most chronic health conditions are made worse by being overweight and that being overweight puts a person at risk for many serious conditions (again, remember that the folks in this study made it to 65 in good health).

    Weight and Longevity

    Of course, if you want to live to 100, this study may not tell us too much. It could be that weight has an impact on life expectancy past a 20+ year horizon. At 65, most people have a life expectancy of just over 20 years.

    If you want to live longer, it could be that you need to do more to stay healthy for 35+ more years.

    The bottom line? We don’t know from data what the ideal weight patterns are for longevity, but we do know from studying people who make it to 100 that being a “healthy” weight seems to be an important factor.

    Source(s):

    Diehr P, O’Meara ES, Fitzpatrick A, Newman AB, Kuller L, Burke G. Weight, mortality, years of healthy life, an active life expectancy in older adults. Journal of the American Geriatrics Society 2008 January to May: 56(1): 76 -- 83.

    Assessing Your Weight and Health Risk. National Heart, Lung and Blood Institute, National Institutes of Health. Accessed 1/20/16.​

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